This movie shows the thin-film micro-ECoG device being pressed down on the surface of water in a petri dish. The ultraflexible nature of the implant means that it cannot exert enough force to break the surface tension of the water. And the properties of polymer used allow it to stick and grab on to the water’s surface. The same thing happens when it is placed on the hydrated surface of the brain, allowing the implant to float with the brain as it moves within the skull without losing contact with the cortical surface.

In the first part of this time-lapse video, an immune cell equipped with a tiny polymer backpack gambols across a microscope slide for some six hours before getting stuck. In the second part of the video, cells with backpacks full of magnetic nanoparticles are tugged toward a magnet, while cells without backpacks stay put.